Ray Chiesa, owner of D. Berta Produce, was up early Friday morning to cut spinach and other field greens to sell at his tidy, colorful stand on Highway 92 in Half Moon Bay.

A box of the fresh, dark-leafed vegetable, which in one week has plummeted from its status as a nutritional standout to the most stigmatized leafy green in modern times, sat in the corner, for sale at $1.25 a bunch.

Meanwhile, roughly 100 miles to the south, hundreds of state and federal public health inspectors were trampling over spinach fields and scrutinizing factories, seeking the source of a pathogen, E. coli 0157:H7, that has sickened more than 150 people and killed at least one.

Investigators have traced the source of the outbreak to contaminated bagged spinach from at least one of nine farms and several processing plants in Monterey, San Benito and Santa Clara counties. Grocery stores and restaurants nationwide swiftly cleared their inventory of fresh spinach after the Food and Drug Administration on Sept. 14 warned consumers not to eat fresh spinach until further notice. On Friday, federal officials lifted their advisory, although still warning consumers not to eat spinach grown in the three affected counties until more stringent safety guidelines are in place there.

Yet, like many small farmers throughout the state, Chiesa had not been heeding the FDA’s warning. In his view, those large farms and processing plants are worlds away from his operation.

“They’re different. We’re not like them,” Chiesa said, explaining how his agricultural practices would render the likelihood of an E. coli contamination extremely remote.

That is a view shared by Sierra Valley Farms in Beckwourth, a small town north of Truckee. At the farm, sales of fresh spinach, as well as lettuce, broccoli and other produce, actually has increased since the Sept. 14 warning.

“We don’t use fertilizer. We use the old traditional way of cover-cropping, rotating and tilling,” said Kim Ramos, who runs the farm with her husband, explaining a millennium-old practice for fertilizing soil naturally. Some fertilizer contains manure, which potentially could be contaminated with E. coli.

“We don’t have a packing plant,” Ramos continued, “My husband and I pick the vegetables, we pack them, and within a day or two you are eating them. So they’re not going through a bunch of peoples’ hands.”

Their customers, Ramos emphasized, trust that the produce is safe to eat. And theyve been spreading the word, she said, telling others to buy from the farm.

People are just saying Lets go with the grower we know, the smaller place,'” she said.

One restaurant, Moodys Bistro and Lounge in Truckee, is selling dishes using spinach purchased from Sierra Valley Farms, she said, adhering to a practice of many chefs to buy from local farmers.

The chefs say its really important to buy from your farmers market and get to know the people who grow it, Ramos said.

I think the local food economy has not been seriously disturbed by this, noted Michael Pollan, author of the best-selling book, The Omnivores Dilemma: A Natural History of Four Meals, and an influential advocate for purchasing food locally.

Pollan said at the farmers market in North Berkeley on Thursday, several vendors were selling fresh spinach at a brisk rate and the box of produce delivered to his home this week from a local farm also contained spinach.

This recent outbreak, one of an increasing number affecting produce as demand increases from health-conscious consumers and farms and processing plants grow in size, reflects the higher risk of contamination associated with large-scale food operations, Pollan noted.

Were washing the national salad in the same sink, he said. The kinds of risks that are inherent in highly centralized production systems, then sold to millions of people, have certain kinds of risk the smaller operations dont.

Pollan also emphasized that this particular strain of Escherichia coli — of which there are many benign strains — is fostered by the practice of feeding cattle with grain. Its become widespread in agriculture for that reason. This strain of E. coli contaminating bagged spinach comes from fecal matter, and is particularly virulent because it can survive in the highly acidic environment of the stomach, unlike most other strains of E. coli.

The fact is industry created this new bug, and we really are dependent upon the zealousness of farmers to protect produce from microbial contamination, Pollan said.

Pollan added that small farmers following unhygienic farming or processing practices could end up with produce contaminated with bacteria, but he said the effect would be much smaller and more readily contained. He added that while more than 150 documented cases of human E. coli infections have been linked to bagged spinach, there were likely far more milder and unreported cases.

Large growers may soon begin heeding the success of small farmers in maintaining customer confidence. Among the voluntary guidelines under consideration to prevent future contamination of produce, as well as revive the moribund industry, includes a recommendation to label the region of the produces origin.

Initially, thats aimed to assure consumers that the spinach isnt from the Salinas Valley, the region implicated in the current outbreak, according to Dr. David Acheson, chief medical officer at the Food and Drug Administrations Center for Food Safety and Applied Nutrition. During the past decade, eight other E. coli outbreaks have been linked to lettuce grown in the Salinas Valley. Last year, the FDA warned local growers of a persistent E. coli problem.

Next week, the FDA will also be reviewing voluntary guidelines offered by the produce industry to ensure agricultural and processing practices with spinach — and other leafy greens.

The proposed guidelines would cover the three Ws of potential contamination — water, workforce and wildlife, said Thomas Nassif, president of Western Growers, which represents some 3,000 farmers and shippers in California and Arizona, who produce about half of all the fresh produce in the country.

His group wants to keep the guidelines voluntary. Obviously, the industry and most of the regulators would like to see us handle it, Nassif said.

The outbreak has derailed the spinach produce industry, and will cause an estimated $50 million to $100 million in losses monthly, according to the Produce Marketing Association.

The one thing that is more fragile than this product is consumer confidence, and the trust consumers have in us as farmers, processors, retailers and restaurant operators, Nassif added. Thats what weve got to focus on.

At Chiesas produce stand, which has been in his wifes family since 1934, sales of spinach have dropped off slightly, although he keeps selling it. A woman told Chiesa that there was no way she was going to buy any spinach. One man visiting G. Bertas on Friday morning overheard Chiesa recount the conversation, and the man, a coastal resident whos known Chiesa for years, said, Good grief, she said that about this stand?

Chiesa nodded with a smile. And while farmers in the Salinas Valley continue to grapple with a crisis that will almost certainly alter the way they grow field greens in the future, Chiesa plans to keep farming his 13-acre plot, furrowed with rows of earth growing Swiss chard, lettuce, beets, carrots, spinach and other produce, the same way.

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